JPH0690509B2 - Lithographic printing original plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photosensitive lithographic printing original plate, and more specifically,
Easy-to-process lithographic printing original plate (hereinafter abbreviated as PS plate)
Regarding

[Prior Art] PS having a photosensitive layer formed by coating a composition containing silver halide and a vinyl compound on an aluminum support
The plates are, for example, JP-A-57-211146 and 58-
It is disclosed in Japanese Patent No. 16231. The method for producing a lithographic printing plate from this PS plate comprises the following steps. That is, a step of pattern-exposing the PS plate (exposure step), then a step of immersing this in a developing solution, washing with water, eluting the photosensitive layer in the unexposed area (developing step), and further removing the photosensitive layer It comprises a step of applying gum arabic or the like to the surface of the aluminum support in order to prevent the surface of the aluminum support from being exposed to the air and decreasing its hydrophilicity. The PS plate described above has high sensitivity because it utilizes the photosensitivity of silver halide, but as described above, in the developing step, a method of removing the photosensitive layer using a developer, a so-called wet development processing method is used. Therefore, not only is the manufacturing process complicated, but there are also unfavorable points such as on satellites, pollution, and safety, depending on the chemicals used.

[Object of the Invention] It is an object of the present invention to provide a lithographic printing plate precursor (PS plate) that can obtain a lithographic printing plate by a simple method without using a developing solution, that is, without a wet development process. And

SUMMARY OF THE INVENTION The present invention comprises a hydrophilic support, a silver halide, a reducing agent,
A lithographic printing original plate is provided with a photosensitive layer containing a microcapsule containing a polymerizable compound and a hydrophilic binder.

[Effect of the Invention] In the PS plate of the present invention, since the core material such as silver halide has a photosensitive layer contained in microcapsules, after exposure / heat development (primary heating), heating (secondary heating) By applying pressure and / or pressure, the polymerizable layer is eluted by softening and destroying the portion of the photosensitive layer that is removed by washing off after the microcapsules are hardened and the capsules of the uncured portions are softened. It is divided into Therefore, the image area (ink-accepting area) and the non-image area (hydrophilic area) are easily formed on the photosensitive layer.

That is, after the treatments such as the above heating (secondary heating), the uncured microcapsules (capsules in the image area) are present in a portion where the capsules are softened, destroyed, etc. It becomes a film (image area). On the other hand, the part where the microcapsules (capsules in the non-image area) in which the polymerizable compound in the part where the latent image of silver halide is formed (or the part where the latent image is not formed) is polymerized and hardened are present by the hydrophilic binder. Because it is still surrounded,
It can be easily removed from the support, and the removed part of the support provides a hydrophilic surface (non-image area).

Therefore, the PS plate of the present invention can be easily obtained as a lithographic printing plate after development by heating without exposure to a developer and further by heating and / or pressing.

[Detailed Description of the Invention] The lithographic printing plate precursor (PS plate) of the invention comprises a hydrophilic support, microcapsules containing silver halide, a reducing agent and a polymerizable compound, and a hydrophilic support. And a photosensitive layer containing a polar binder.

As the silver halide used in the PS plate of the present invention, silver halide known in the photographic art can be used. In the present invention, any grains of silver chloride, silver bromide, silver iodide or silver chlorobromide, silver chloroiodide, silver iodobromide and silver chloroiodobromide can be used.

The halogen composition of the silver halide grains may be uniform or non-uniform on the surface and inside. Regarding silver halide grains having a multiple structure having different compositions on the surface and in the inside, JP-A-57-154232, JP-A-58-108533, and JP-A-59-4875.
5, No. 59-52237, U.S. Pat. No. 4,433,048 and European Patent No. 100,984. Further, as used in the light-sensitive material described in Japanese Patent Application No. 61-25576, silver halide grains having a high silver iodide ratio in the shell portion may be used.

There is also no particular limitation on the crystal habit of the silver halide grains. For example, tabular grains having an aspect ratio of 3 or more as in the light-sensitive material described in Japanese Patent Application No. 61-55509 may be used.

The silver halide used in the present invention may be used in combination with two or more kinds of silver halide grains having different halogen compositions, crystal habits, grain sizes and the like.

The grain size distribution of silver halide grains is not particularly limited. For example, monodisperse silver halide grains having a substantially uniform grain size distribution may be used as in the light-sensitive material described in Japanese Patent Application No. 61-55508.

In the present invention, the average grain size of the silver halide grains is preferably 0.001 to 10 μm, more preferably 0.001 to 5 μm.

The amount of silver halide contained in the photosensitive layer is 0.1 mg to 10 g / m ^{2 in} terms of silver including an organic silver salt which is an optional component described later.
It is preferable to set it as the range.

The reducing agent that can be used in the PS plate of the present invention has a function of reducing silver halide and / or a function of accelerating (or suppressing) the polymerization of the polymerizable compound. There are various kinds of substances as the reducing agent having the above function. Examples of the reducing agent include hydroquinones, catechols, p-aminophenols, p-phenylenediamines, 3-pyrazolidones, 3-aminopyrazoles, 4-amino-
5-virazolones, 5-aminouracils, 4,5-dihydroxy-6-aminopyrimidines, reductones, aminoreductones, o- or p-sulfonamidophenols, o- or p-sulfonamidonaphthols, 2 -Sulfonamidoindanones, 4-sulfonamido-5-pyrazolones, 3-sulfonamidoindoles, sulfonamidopyrazolobenzimidazoles,
Examples include sulfonamide pyrazolotriazoles, α-sulfonamide ketones, and hydrazines. By adjusting the type and amount of the reducing agent, it is possible to polymerize the polymerizable compound in the portion where the latent image of silver halide is formed or the portion where the latent image is not formed.
In the system in which the polymerizable compound in the portion where the latent image of silver halide is not formed is polymerized, it is particularly preferable to use 1-phenyl-3-pyrazolidones as the reducing agent.

Regarding the various reducing agents having the above functions, Japanese Patent Application No.
60-22980, 60-29894, 60-68874, 60-2
No. 10657, No. 60-226084, No. 60-227527, No. 60-227
No. 528 and No. 61-42746 are described (including those described as a developing agent or a hydrazine derivative). Regarding the reducing agent, see “The Theory of t” by T. James.
he Photographic Process "4th edition, pages 291-334 (1977
Year), Research Disclosure Vol.170, Issue 17029, June 1978 (pages 9-15), and Vol.176,197.
It is also described in No. 17643 (pages 22 to 31), December 1988. Further, as in the light-sensitive material described in Japanese Patent Application No. 61-55505, a reducing agent precursor capable of releasing the reducing agent under heating conditions or in contact with a base is used instead of the reducing agent. May be. Also in the PS plate of the present invention, the reducing agent and reducing agent precursor described in the above-mentioned respective specifications and references can be effectively used. Therefore, the “reducing agent” in the present specification includes the reducing agents and reducing agent precursors described in the above respective specifications and literatures.

These reducing agents may be used alone, or as described in each of the above specifications, two or more reducing agents may be mixed and used. When two or more reducing agents are used in combination, the reducing agents may interact with each other by first promoting the reduction of silver halide (and / or organic silver salt) by so-called superadditivity. To cause polymerization of the polymerizable compound via an oxidation-reduction reaction with another reducing agent in which the oxidant of the first reducing agent generated by reduction of silver halide (and / or organic silver salt) coexists (Or suppressing the polymerization) is considered. However, in actual use, it is difficult to specify which of the above actions, because the above reactions may occur simultaneously.

Specific examples of the reducing agent include pentadecylhydroquinone, 5-t-butylcatechol, p- (N, N-diethylamino) phenol, 1-phenyl-4-methyl-4.
-Hydroxymethyl-3-pyrazolidone, 1-phenyl-4-methyl-4-heptadecylcarbonyloxymethyl-3-pyrazolidone, 2-phenylsulfonylamino-4-hexadecyloxy-5-t-octylphenol, 2-phenylsulfonyl Amino-4-t-butyl-
5-hexadecyloxyphenol, 2- (N-butylcarbamoyl) -4-phenylsulfonylaminonaphthol, 2- (N-methyl-N-octadecylcarbamoyl) -4-sulfonylaminonaphthol, 1-acetyl-2-phenylhydrazine , 1-acetyl-2-{(p
Or o) -aminophenyl} hydrazine, 1-formyl-2-{(p or o) -aminophenyl} hydrazine, 1-acetyl-2-{(p or o) -methoxyphenyl} hydrazine, 1-lauroyl-2 -{(P or o) -aminophenyl} hydrazine, 1-trityl-
2- (2,6-dichloro-4-cyanophenyl) hydrazine, 1-trityl-2-phenylhydrazine, 1-phenyl-2- (2,4,6-trichlorophenyl) hydrazine, 1- {2- (2 , 5-di-t-pentylphenoxy)
Butyroyl} -2-{(p or o) -aminophenyl} hydrazine, 1- {2- (2,5-di-t-pentylphenoxy) butyroyl} -2-{(p or o) -aminophenyl} hydrazine -Pentadecyl fluorocaprylate, 3-indazolinone, 1- (3,5-dichlorobenzoyl) -2-phenylhydrazine, 1-trityl-2-[{2-N-butyl-N-octylsulfamoyl)- 4-methanesulfonyl} phenyl] hydrazine,
1- {4- (2,5-di-t-pentylphenoxy) butyroyl} -2-{(p or o) -methoxyphenyl}
Hydrazine, 1- (methoxycarbonylbenzohydryl) -2-phenylhydrazine, 1-formyl-2-
[4- {2- (2,4-di-t-pentylphenoxy) butylamido} phenyl] hydrazine, 1-acetyl-2
-[4- {2- (2,4-di-t-pentylphenoxy)
Butylamido} phenyl] hydrazine, 1-trityl-
2-[{2,6-dichloro-4- (N, N-di-2-ethylhexyl) carbamoyl} phenyl] hydrazine, 1-
(Methoxycarbonylbenzohydryl) -2- (2,4-
Dichlorophenyl) hydrazine, 1-trityl-2-
[{2- (N-ethyl-N-octylsulfamoyl)
-4-Methanesulfonyl} phenyl] hydrazine, 1-
Benzoyl-2-tritylhydrazine, 1- (4-butoxybenzoyl) -2-tritylhydrazine, 1- (2,
4-dimethoxybenzoyl) -2-tritylhydrazine, 1- (4-dibutylcarbamoylbenzoyl) -2
-Tritylhydrazine, and 1- (1-naphthoyl)
-2-Trityl hydrazine etc. can be mentioned.

In the PS plate of the present invention, the reducing agent is preferably used in the range of 0.1 to 1500 mol% with respect to 1 mol of silver (including the above-described silver halide and an organic silver salt which is an optional component).

The polymerizable compound that can be used in the PS plate of the present invention is not particularly limited, and known polymerizable compounds can be used. As a method of using the PS plate, when a heat development treatment is planned, a high boiling point (for example, a boiling point of 80
It is preferable to use compounds of (° C. or higher).

The polymerizable compound used in the PS plate of the present invention is generally a compound having addition polymerization or ring-opening polymerization. The compound having an addition polymerizable property includes a compound having an ethylenically unsaturated group, and the compound having a cleavable polymerization property includes a compound having an epoxy group. A compound having an ethylenically unsaturated group is particularly preferable.

The compound having an ethylenically unsaturated group that can be used in the PS plate of the present invention includes acrylic acid and salts thereof, acrylic acid esters, acrylamides, methacrylic acid and salts thereof, methacrylic acid esters, methacrylamides. , Maleic anhydride, maleic acid esters, itaconic acid esters, styrenes, vinyl ethers, vinyl esters, N-vinyl complex compounds, allyl ethers, allyl esters and their derivatives.

Specific examples of the polymerizable compound that can be used in the present invention include acrylic acid esters such as n-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, benzyl acrylate, furfuryl acrylate, ethoxyethoxyethyl acrylate, dicyclohexyloxy. Ethyl acrylate, nonylphenyloxyethyl acrylate, hexanediol diacrylate, butanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate,
Examples thereof include polyoxyethylenated bisphenol A diacrylate, hydroxypolyether polyacrylate, polyester acrylate, and polyurethane acrylate.

Other specific examples of methacrylic acid esters include methyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, butanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, and pentaerythritol tetramethacrylate. Methacrylate and dimethacrylate of polyoxyalkylenated bisphenol A and the like can be mentioned.

The polymerizable compounds may be used alone or in combination of two or more.

In addition, a substance in which a polymerizable functional group such as a vinyl group or a vinylidene group is introduced into the chemical structure of the reducing agent described above can also be used as the polymerizable compound of the present invention. Needless to say, the use of a substance that serves as a reducing agent and a polymerizable compound as described above is also included in the embodiments of the present invention.

In the PS plate of the present invention, the polymerizable compound is silver halide 1
It is preferably used in the range of ^{5 to} 1.2 × 10 ⁵ parts by weight based on parts by weight. A more preferable range of use is 12 to 1.2.
× 10 ⁴ parts by weight.

In the PS plate of the present invention, the silver halide, the reducing agent and the polymerizable compound described above are contained in the photosensitive layer in a state of being contained in microcapsules.

In the present specification, the “substance contained in the microcapsule” means the substance existing in the core substance and / or the wall material forming the microcapsule.

Various known techniques can be applied to the microcapsules without particular limitation.

Examples of the above-mentioned known technique include a method utilizing coacervation of a hydrophilic wall forming material described in US Pat. Nos. 280457 and 2800458; US Pat. No. 3287154 and British Patent No. 990443. Book and Japanese Examined Sho 38-
19574, 42-446, and 42-771, respectively, interfacial polymerization method; method by precipitation of polymer described in U.S. Pat. Nos. 3,418,250 and 3,660,304; U.S. Pat.
Method using isocyanate-polyol wall material described in 3796669; Method using isocyanate wall material described in US Pat. No. 3,914,511; US Pat.
No. 0, No. 4087376 and No. 4089802, the method using the urea-formaldehyde-based or urea-formaldehyde-resorcinol-based wall forming material; the melamine-formaldehyde resin and hydroxypropyl described in US Pat. No. 4025455. A method using a wall forming material such as cellulose; JP-B-36-9168 and JP-A-51-90.
In situ method by polymerization of monomers described in No. 79 publications; electrolytic dispersion cooling method described in each of British Patent Nos. 952807 and 965074; US Patent No. 3111407 and British Patent No. 9
The spray drying method described in each specification of No. 30422 can be mentioned. The method of microencapsulation is not limited to the above, but a method of forming a polymer film as a microcapsule wall after emulsifying the core substance is particularly preferable.

There is no particular limitation on the wall material of the microcapsule formed based on the above-mentioned known technique. However, the microcapsule wall material that can be used more advantageously in the present invention is preferably a lipophilic wall material that exhibits a contact angle with water of 40 degrees or more. As such a wall material, polyurea, polyurethane, polyethylene, polyamide, polyester, polycarbonate, polyethyleneamine, phenol formalin resin, melamine resin, vinyl polymer and vinyl copolymer, polyacrylonitrile, polyvinyl acetal resin, cellulose acetate, polyethylene. , Polypropylene, polybutadiene and the like, and mixtures thereof.

The above-mentioned microcapsule wall material is preferably a wall material exhibiting thermal softening property by relatively low heating (secondary heating), that is, a wall material having relatively low glass transition temperature. If the glass transition temperature is low, it is softened at a low temperature, and the polymerizable monomer is leached from the microcapsules (including the core substance) in the uncured portion, so that a lipophilic and uniform film as the image area can be easily formed. Such glass transition temperature is preferably in the range of 80 to 300 ℃, more preferably 80 to 250 ℃
And in the range of 80 to 220 ° C. However, the above glass transition temperature is a value measured by using Hybron DDV-II type (manufactured by Toyo Baldwin Co., Ltd.) at a heating rate of 2 ° C./min. When the glass transition temperature is lower than the above range, the microcapsules have poor stability over time. Further, when the glass transition temperature is higher than the above range, the heating temperature must be set high, which adversely affects the support itself.

From the above viewpoints, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, or a mixture thereof, and particularly preferably polyurea and polyurethane.

The particle size of the microcapsules formed of such a wall material is preferably in the range of 0.01 to 30 μm, and particularly preferably in the range of 0.01 to 10 μm from the viewpoint of handling and the like, and from the viewpoint of resolution. 0.01 to 5 μm
It is preferably in the range of.

The hydrophilic binder used in the PS plate of the present invention is preferably transparent or translucent. Such hydrophilic binders include gelatin, gelatin derivatives, carboxymethylcellulose, cellulose derivatives such as methylcellulose, starch, natural substances such as polysaccharides such as arabic gum, polyvinyl alcohol, polyvinylpyrrolidone, acrylamide polymers, polyacrylic acid, Mention may be made of synthetic polymeric substances such as water-soluble polyvinyl compounds such as vinyl acetate-acrylic acid copolymers. The above can be used alone or in appropriate combination.

The hydrophilic support used in the present invention can be appropriately selected from known support materials and used. Specifically, paper, synthetic paper, paper laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), aluminum (including aluminum alloy), metal plates such as zinc, iron, copper, cellulose acetate , A plastic film such as cellulose propionate, cellulose butyrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, and a paper or plastic film on which the above metal is laminated or vapor deposited. Of these, paper, synthetic paper, polyethylene terephthalate, polycarbonate, and aluminum plate are preferable. The paper support is described in JP-A Nos. 61-3797 and 61-112150.

These supports are subjected to surface roughening treatment (graining treatment) or surface hydrophilic treatment as necessary.

The case where an aluminum plate is used as the support will be described below as an example.

Surface treatment (graining treatment) is an electrochemical graining method in which an aluminum plate is subjected to electricity in hydrochloric acid or nitric acid electrolytic solution to grain, and an aluminum surface is scratched with a metal wire by a wire brush grain method, a polishing ball. And a mechanical graining method such as a ball grain method of graining the aluminum surface with an abrasive and a brush grain method of graining the surface with a nylon brush and an abrasive. To be done.

The thus grained aluminum is then chemically etched with an acid or alkali. An industrially advantageous method is etching using an alkali.

As the alkaline agent preferably used for these purposes,
Examples thereof include sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, sodium hydroxide, potassium hydroxide and lithium hydroxide.
And, the preferred range of the concentration and the temperature at which this alkaline solution is used are 1 to 50% by weight and 20 to 100 ° C., respectively, and the preferred range is such that the amount of aluminum dissolved is 5 to 20 g / m ^2. Is chosen as.

Further, usually, after the alkali etching, pickling is performed in order to remove stains (smut) remaining on the surface. Suitable acids are nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borofluoric acid and the like.

Incidentally, the smut removal treatment after the electrochemical graining treatment, as described in JP-A-53-12739, 5
A method of contacting with sulfuric acid having a concentration of 15 to 65% by weight at a temperature of 0 to 90 ° C or a method described in JP-B-48-28123 is effective.

As described above, the surface-roughened aluminum support is obtained, but if desired, it may be subjected to anodizing treatment or chemical conversion treatment.

The anodizing treatment can be performed by a known method that has been conventionally performed in this field. Specifically, this method involves applying direct current or alternating current to aluminum in a solution or aqueous solution of sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc., or a combination of two or more thereof. Is a method of forming an anodized film on the surface of aluminum.

The treatment conditions for the above anodic oxidation cannot be unconditionally determined because they vary depending on the electrolytic solution used, but generally the concentration of the electrolytic solution is 1 to 80% by weight, and the temperature of the electrolytic solution is 5 to 70%.
℃, current density 0.5-60 amps / dm ² , voltage 1-100
Suitably V, and the electrolysis time is in the range of 10 to 100 seconds.

In particular, the anodizing method is described in British Patent No. 1412768, a method of anodizing at high current density in sulfuric acid or described in U.S. Pat.No. 3511661, phosphoric acid as an electrolytic bath. The method of anodic oxidation is preferable.

Anodized aluminum plates are further described in US Pat.
2714066 and 3181461, as described in U.S. Pat. No. 3,860,426, which may be treated with an alkali metal silicate (for example, by dipping in an aqueous solution of sodium silicate). As described above, an undercoat layer made of hydrophilic cellulose (eg, carboxymethyl cellulose) containing a water-soluble metal salt (eg, zinc acetate) can be provided.

Hereinafter, various aspects of the PS plate of the present invention, optional components that can be contained in the photosensitive layer, and auxiliary layers that can be optionally provided in the PS plate will be sequentially described.

As described above, the PS plate of the present invention contains silver halide, a reducing agent, and a polymerizable compound in microcapsules. The microcapsules may contain any component that can be contained in the photosensitive layer described later. When the silver halide is contained in the microcapsules, it is preferable that the silver halide be present in the wall material forming the outer shell of the microcapsules.

As an optional component that can be contained in the photosensitive layer of the PS plate of the present invention, a color image forming substance, a sensitizing dye, an organic silver salt, various image forming accelerators (eg, base or base precursor,
Oil, surfactant, compound having antifoggant function and / or development promoting function, thermal solvent, compound having oxygen removing function, etc.), thermal polymerization inhibitor, thermal polymerization initiator, development stopper, fluorescent whitening Agents, anti-fading agents, halation or anti-irradiation dyes, matting agents, anti-smudge agents, plasticizers, water releasing agents, binders, photopolymerization initiators, solvents for polymerizable compounds, and the like.

The color image-forming substance that can be used in the PS plate of the present invention is not particularly limited, and various types can be used. By including the color image forming substance in the photosensitive layer, the image area or the non-image area can be colored, and the two can be easily distinguished. Examples of such substances are substances that are colored by themselves (pigments or dyes), or energy that is colorless or light but is external (heat, pressure, light irradiation, etc.), or another component. Substance that develops color by contact with (developing agent) (coloring agent)
Are also included in the color image forming materials that can be used in the present invention. The color image-forming substance is described in detail in the light-sensitive material described in JP-A No. 61-73145. Further, Japanese Patent Application No. 61-29987 describes a photosensitive material using a dye or pigment as a color image forming substance, and Japanese Patent Application Nos. 61-53876 and 61-53876 describe a photosensitive material using a leuco dye.
No. 133091 and No. 61-133092, and the color image-forming substances used therein are also applicable to the PS plate of the present invention.

The sensitizing dye that can be used in the present invention is not particularly limited, and a silver halide sensitizing dye known in the photographic art and the like can be used. The sensitizing dyes include methine dyes, cyanine dyes, merocyanine dyes, complex cyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes.
These sensitizing dyes may be used alone or in combination. In particular, for the purpose of supersensitization, it is common to use a combination of sensitizing dyes. Further, together with the sensitizing dye, a dye which does not have a spectral sensitizing effect itself, or a substance which does not substantially absorb visible light but exhibits supersensitization may be used together. The addition amount of the sensitizing dye is generally about 10 ^{-8 to} 10 ^-2 mol per mol of silver halide. The sensitizing dye is preferably added at the stage of preparing a silver halide emulsion described below.

Specific examples of the sensitizing dye are described in the above-mentioned Japanese Patent Application Nos. 60-139746 and 61-55510, and these sensitizing dyes can also be used.

In the present invention, the addition of the organic silver salt is particularly effective in the heat development processing. That is, when heated to a temperature of 80 ° C. or higher, the organic silver salt is considered to participate in the redox reaction using the latent image of silver halide as a catalyst. In this case, it is preferable that the silver halide and the organic silver salt are in contact with or in close proximity to each other. Examples of the organic compound that constitutes the organic silver salt include an aliphatic or aromatic carboxylic acid, a thiocarbonyl group-containing compound having a mercapto group or α-hydrogen, and an imino group-containing compound. Among them, benzotriazole is particularly preferable. The above organic silver salt is generally used in an amount of 0.01 to 10 mol, preferably 0.01 to 1 mol, per mol of silver halide. The same effect can be obtained by adding an organic compound (for example, benzotriazole) constituting the organic silver salt to the photosensitive layer instead of the organic silver salt. Specific examples of organic silver salts are described in the light-sensitive material of Japanese Patent Application No. 60-141799.

Various image forming accelerators can be used in the PS plate of the present invention. The silver halide (and //
Alternatively, it has a function of promoting the redox reaction between the redox agent and the organic silver salt). The image forming accelerator is a base or a base precursor, an oil, a surfactant, a compound having an antifoggant function and / or a development promoting function, a thermal solvent, a compound having an oxygen removing function, etc. Is further classified into. However, these substance groups generally have a composite function, and usually have some of the above-mentioned accelerating effects together. Therefore, the above classification is convenient, and in fact, one compound often has a plurality of functions.

Examples of image forming accelerators include bases, base precursors, oils, surfactants, compounds having an antifoggant function and / or development promoting function, thermal solvents, and compounds having an oxygen removing function.

Examples of preferable bases include alkali metal or alkaline earth metal hydroxides as inorganic bases; alkali metal or alkaline earth metal tertiary phosphates, borates,
Carbonates, metaborates; combinations of zinc hydroxide or zinc oxide with chelating agents such as sodium picolinate;
Ammonium hydroxides; quaternary alkyl ammonium hydroxides; hydroxides of other metals, and the like, and organic bases include aliphatic amines (trialkylamines,
Hydroxylamines, aliphatic polyamines); Aromatic amines (N-alkyl-substituted aromatic amines, N-hydroxylalkyl-substituted aromatic amines and bis [p-
(Dialkylamino) phenyl] methanes), heterocyclic amines, amidines, cyclic amidines, guanidines, cyclic guanidines, and the like, with a pKa of 7 or more being particularly preferable.

Examples of the base precursor include salts of organic acids and bases that are decarboxylated by heating, compounds that release amines by reactions such as intramolecular nucleophilic substitution reaction, Rossen rearrangement, Beckmann rearrangement, etc. Compounds that release and generate a base by electrolysis are preferably used. Specific examples of the base precursor include guanidine trichloroacetic acid, piperidine trichloroacetic acid, morpholine trichloroacetic acid, p-toluidine trichloroacetic acid, 2-picoline trichloroacetic acid, phenylsulfonylacetic acid guanidine, 4-chlorophenylsulfonylacetic acid guanidine, and 4-methyl-sulfonyl. Examples thereof include guanidine phenylsulfonylacetate and guanidine 4-acetylaminomethylpropiolate.

The base or base precursor can be used in a wide range of amounts in the PS plate of the present invention. The base or base precursor is suitably used in an amount of 100% by weight or less, more preferably 0.1% by weight, based on the weight of the coating film of the photosensitive layer.
A range of from 40% by weight is useful. In the present invention, the base and / or base precursor may be used alone or as a mixture of two or more kinds.

Further, regarding a light-sensitive material using a tertiary amine as a base or a base precursor, Japanese Patent Application No. 61-13181 uses a fine particle dispersion of a hydrophobic organic base compound having a melting point of 80 to 180 ° C. For the photosensitive material,
No. 52992, the light-sensitive material using a hydroxide or salt of an alkali metal or an alkaline earth metal, each of which is described in Japanese Patent Application No. 61-96341, the base used in these, The base precursor is also of the present invention.
It can be used for PS version.

When a base or base precursor is used in the PS plate of the present invention, it is preferable that the base or base precursor is present in the photosensitive layer outside the microcapsules described above.
Alternatively, the base or the base precursor may be contained in a microcapsule different from the above microcapsule, or may be added to an auxiliary layer other than the photosensitive layer (a layer containing the base or the base precursor described later). .

As the oil, a high boiling point organic solvent used as a solvent for emulsifying and dispersing a hydrophobic compound can be used.

Examples of the surfactant include pyridinium salts described in JP-A-59-74547, ammonium salts, phosphonium salts, polyalkylene oxides described in JP-A-59-57231, and the like. Can also be used in the PS version of the present invention.

The compound having the fog-preventing function and / or the development-accelerating function can be used for the purpose of clearly obtaining the image area and the non-image area. Incidentally, regarding a photosensitive material using an antifoggant as a compound having an antifoggant function and / or a development promoting function, Japanese Patent Application No. 60-294337 discloses a photosensitive material using a compound having a cyclic amide structure. Japanese Patent Application No. 60-294338 discloses a light-sensitive material using a thioether compound in Japanese Patent Application No. 60-2943.
39, Japanese Patent Application No. 60-294340 for a photosensitive material using a polyethylene glycol derivative, Japanese Patent Application No. 60-2943 for a photosensitive material using a thiol derivative.
No. 41 describes the light-sensitive material using an acetylene compound in Japanese Patent Application No. 61-20438, and the light-sensitive material using a sulfonamide derivative in Japanese Patent Application No. 25-25578. And the compounds used therein can also be used in the PS plate of the present invention.

As the hot solvent, a compound which can be a solvent for the reducing agent, a compound which is a substance having a high dielectric constant and is known to accelerate the physical development of the silver salt, and the like are useful. As a useful thermal solvent,
Polyethylene glycols described in U.S. Pat. No. 3,347,675, derivatives of polyethylene oxide such as oleic acid ester, beeswax, monostearin, high-dielectric constant compounds having --SO ₂ --and / or --CO-- groups, U.S. Pat. The polar substances described in Japanese Patent No. 3667959, 1,10-decanediol, methyl anisate, biphenyl suberate and the like described in Research Disclosure, December 1976, pages 26 to 28 are preferably used.

The compound having a function of removing oxygen can be used for the purpose of eliminating the influence of oxygen during development (oxygen has a polymerization inhibiting action). Examples of the compound having an oxygen removing function include compounds having two or more mercapto groups.

The thermal polymerization initiator that can be used in the PS plate of the present invention is a compound that generally undergoes thermal decomposition under heating to generate a polymerization initiation species (particularly a radical), and is usually used as an initiator for radical polymerization. is there. Regarding the thermal polymerization initiator,
Pp. 6-18, "Addition Polymerization / Ring-Opening Polymerization," 1983, Kyoritsu Shuppan, ed. Specific examples of the thermal polymerization initiator include azobisisobutyronitrile, 1,1′-azobis (1-cyclohexanecarbonitrile), dimethyl-2,2′-azobisisobutyrate, 2,2-azobis ( 2-Methyl butyronitrile), azo compounds such as azobisdimethylvaleronitrile, organic peroxides such as benzoyl peroxide, di-t-peroxide, dicumyl peroxide, t-butylhydroperoxide, cumene hydroperoxide, etc. Compounds, hydrogen peroxide, inorganic peroxides such as potassium persulfate and ammonium persulfate, and sodium p-toluenesulfinate. The thermal polymerization initiator is preferably used in the range of 0.1 to 120% by weight, more preferably 1 to 10% by weight, based on the polymerizable compound. Further, in the case of the present invention, in the system for polymerizing the polymerizable compound in the portion where the latent image of silver halide is not formed,
The thermal polymerization initiator is preferably contained in the microcapsules together with silver halide and the like. A light-sensitive material using a thermal polymerization initiator is described in Japanese Patent Application No. 60-210657, and the thermal polymerization initiator used in these can also be used in the PS plate of the present invention.

The development terminator that can be used in the PS plate of the present invention is a compound or silver and a silver salt which, after proper development, promptly neutralize the base or react with the base to lower the concentration of the base in the film and stop the development. It is a compound that interacts with and suppresses development.
Specifically, an acid precursor that releases an acid by heating,
An electrophilic compound that causes a substitution reaction with a coexisting base upon heating, a nitrogen-containing heterocyclic compound, a mercapto compound, or the like can be given. Examples of acid precursors include JP-A-60
Examples thereof include oxime esters described in JP-A-108837 and JP-A-60-192939, and compounds that release an acid by Rossen rearrangement described in Japanese Patent Application No. 59-85834. Examples of electrophilic compounds that undergo a substitution reaction with a base upon heating include the compounds described in JP-A-60-230134.

The anti-smudge agent used in the PS plate of the present invention is preferably solid particles at room temperature. Specific examples include starch particles described in British Patent No. 12,322,347, U.S. Pat.
Polymer fine powder described in 3,625,736 specification, UK Patent No.
Microcapsule particles containing no color former as described in 1,235,991, etc., cellulose fine powder described in U.S. Pat.No. 2,711,375, talc, kaolin, bentonite, pyrophyllite, zinc oxide, titanium dioxide, inorganic particles such as alumina, etc. Can be mentioned. The average particle size of the particles is preferably in the range of 3 to 50 μm in volume average diameter, and more preferably in the range of 5 to 40 μm. When the polymerizable compound or the like is in the microcapsule state as described above, it is more effective that the particles are larger than the microcapsules.

In addition to the above, examples of optional components that can be contained in the photosensitive layer and usage thereof are also described in the application specification regarding the series of photosensitive materials described above, and Research Disclosure Magazine Vol. 170, June 1978. 17029 (pages 9 to 15).

As the auxiliary layer that can be optionally provided in the PS plate of the present invention, a heating element layer, an antistatic layer, an anti-curl layer, a peeling layer,
Examples thereof include a cover sheet or a protective layer, a layer containing a base or a base precursor, and a base barrier layer.

Hereinafter, a method for manufacturing the PS plate of the present invention will be described.

Although various methods can be used as the method for producing the PS plate, the general method is to prepare a liquid composition by dissolving, emulsifying or dispersing the components of the photosensitive layer in an appropriate solvent. The method comprises the steps of microcapsulating the composition and further preparing a coating solution containing a microcapsule dispersion, and coating the coating solution on a hydrophilic support and drying.

Generally, a coating liquid containing the above-mentioned microcapsule dispersion liquid is prepared by mixing each liquid composition prepared for each component and then microcapsulating the liquid composition. The liquid composition may be prepared for each component, or may be prepared to contain a plurality of components. A part of the components of the photosensitive layer may be added and used at the stage of preparing the liquid composition or the coating solution or after the preparation.
Further, a method of preparing a secondary composition by further emulsifying an oily (or aqueous) composition containing one or more components in an aqueous (or oily) solvent can also be used.

With respect to the main components contained in the photosensitive layer, a method for preparing a liquid composition and a coating liquid is shown below.

In the production of the PS plate of the present invention, silver halide is preferably prepared as a silver halide emulsion. There are various methods known in the photographic art for the preparation of silver halide emulsions, but there is no particular limitation regarding the production of the PS plate of the present invention. The silver halide emulsion can be prepared by any of the acidic method, the neutral method and the ammonia method. The reaction mode of the soluble silver salt and the soluble halogen salt may be a one-sided mixing method, a simultaneous mixing method, or a combination thereof. A back mixing method in which grains are mixed under an excess of silver ions and a controlled double jet method in which pAg is kept constant can also be adopted. Further, the silver halide emulsion may be a surface latent image type in which a latent image is mainly formed on the surface of a grain, or an internal latent image type in which a latent image is formed inside the grain. A direct reversal emulsion in which an internal latent image type emulsion and a nucleating agent are combined can also be used.

In the preparation of the silver halide emulsion used for producing the PS plate of the present invention, it is preferable to use a hydrophilic colloid as the protective colloid. Examples of the hydrophilic colloid include gelatin, gelatin derivatives, graft polymers of gelatin and other polymer substances, proteins such as albumin and casein; derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, cellulose sulfates, sodium alginate. , Starch derivatives and other derivatives;
And various synthetic hydrophilic polymers such as polyvinyl alcohol, polyvinyl alcohol partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole, and other single or copolymers. Mention may be made of substances. Of these, gelatin is preferred. As the gelatin, not only lime-processed gelatin but also acid-processed gelatin and enzyme-processed gelatin may be used, and hydrolyzed products and enzyme-processed decomposition products of gelatin can also be used.

In the production of the PS plate of the present invention, when a silver halide emulsion prepared using a hydrophilic colloid is used, the sensitivity of the PS plate is improved. The silver halide emulsion contains ammonia, an organic thioether derivative (see JP-B-47-386) and a sulfur-containing compound (see JP-A-53-144319) as a silver halide solvent in the step of forming silver halide grains. Etc. can be used. In the process of grain formation or physical ripening, cadmium salt, zinc salt, lead salt,
You may make thallium salt etc. coexist. Higher illumination failure,
For the purpose of improving the low illumination failure, a water-soluble iridium salt such as iridium chloride (III or IV valence), hexachloroiridium salt ammonium, or a water-soluble rhodium salt such as rhodium chloride can be used.

Soluble salts may be removed from the silver halide emulsion after formation of a precipitate or after physical ripening. In this case, it can be carried out according to the Nudel washing method or the sedimentation method. The silver halide emulsion may be used without ripening, but it is usually chemically sensitized before use. In the emulsion for a conventional type light-sensitive material, known sulfur sensitizing method, reduction sensitizing method, noble metal sensitizing method and the like are used alone or in combination, but they can also be applied in the production of the PS plate of the present invention.

When a sensitizing dye is added to the silver halide emulsion,
It is preferably added at the stage of preparing a silver halide emulsion (see Japanese Patent Application Nos. 60-139746 and 61-55510).

When the nitrogen-containing complex-containing compound is added as the compound having the fog-preventing function and / or the development-accelerating function, it should be added in the step of forming silver halide grains or the ripening step in the preparation of silver halide emulsion. Is preferred (see Japanese Patent Application No. 61-3024).

Further, when the above-mentioned organic silver salt is contained in the photosensitive layer,
An organic silver salt emulsion can be prepared by a method similar to the method for preparing a silver halide emulsion described above. And it is preferable that this organic silver salt is also contained in the microcapsules.

In the production of the PS plate of the present invention, the polymerizable compound can be used as a medium for preparing the composition of other components in the photosensitive layer. For example, a silver halide (including a silver halide emulsion), a reducing agent and the like can be dissolved, emulsified or dispersed in a polymerizable compound and used for producing a PS plate.
This allows the above components to be easily dispersed in the oil droplets of the polymerizable compound. Further, in this case, components such as a wall material required for microcapsulation may be included in the oil droplets.

The photosensitive composition containing a polymerizable compound containing silver halide can be prepared using a silver halide emulsion.
In addition to the silver halide emulsion, a silver halide powder prepared by freeze-drying or the like can be used for the preparation of the photosensitive composition.

The photosensitive composition can be obtained by charging the above silver halide, the polymerizable compound, the reducing agent, and other optional components into a commonly used stirrer (homogenizer, blender, mixer, etc.) and stirring. .

In addition, it is preferable to dissolve a copolymer composed of a hydrophilic repeating unit and a hydrophobic repeating unit in the polymerizable compound used for preparing the photosensitive composition (see Japanese Patent Application No. 60-261887). ).

Further, instead of using the above-mentioned copolymer, a photosensitive composition may be prepared by dispersing microcapsules containing a silver halide emulsion as a core substance in a polymerizable compound (Japanese Patent Application No. 61-61).
-5750 specification).

The photosensitive composition thus obtained is then encapsulated according to the method for forming an outer shell described above to prepare a capsule dispersion containing a silver halide, a reducing agent and a polymerizable compound. As described above, some optional components can be added to the microcapsule dispersion liquid.

The above-mentioned hydrophilic binder is added to the capsule dispersion liquid prepared as described above to prepare a photosensitive layer forming coating liquid. At this time, an optional component such as a surfactant may be added if necessary. The hydrophilic binder can be added before the microencapsulation.

The PS plate of the present invention can be produced by applying the coating solution for forming a photosensitive layer thus prepared onto the hydrophilic support described above and drying. The coating of the coating liquid on the support can be easily carried out according to known techniques.

Next, a method of using the PS plate of the present invention will be described.

The PS plate of the present invention is used by being subjected to a development treatment simultaneously with or after the imagewise exposure, and then a lipophilic film-forming treatment of the unpolymerized portion.

As the above-mentioned exposure method, various exposure means can be used, but generally a latent image of silver halide is obtained by imagewise exposure to radiation including visible light. The type of light source and the amount of exposure can be selected according to the photosensitive wavelength of silver halide (the wavelength sensitized when dye sensitization is performed) and the sensitivity. Examples of these include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a carbon arc lamp, a tungsten lamp or an infrared lamp. Scanning exposure with a laser beam can also be used in the present invention. Examples of such a laser beam include a semiconductor laser, a helium / neon laser, an argon laser, a krypton ion laser, and a helium / cadmium laser.

As described above, the PS plate of the present invention has the advantage that the method of performing heat development treatment (see JP-A-61-69062) is simple in operation and can be treated in a short time. Therefore, it is adopted as a preferable development processing method.

As a heating (primary heating) method in the heat development treatment, various conventionally known methods can be used. As the heat development treatment, a method of providing a heating material layer on a photosensitive material and using it as a heating means, such as the photosensitive material described in Japanese Patent Application No. 60-135568, or Japanese Patent Application No.
As the image forming method described in the specification of No. 55506, a method of carrying out a heat development treatment while suppressing the amount of oxygen present in the photosensitive layer can be used. Heating temperature is generally 80 ℃
To 200 ° C, preferably 100 ° C to 160 ° C. The heating time is generally 1 second to 5 minutes, preferably 5 seconds to 1
Minutes.

The PS plate of the present invention is subjected to heat development treatment as described above,
It is possible to polymerize the polymerizable compound in a portion where a latent image of silver halide is formed or a portion where a latent image of silver halide is not formed. In the PS plate of the present invention, generally, in the heat development treatment, the polymerizable compound in the portion where the latent image of silver halide is formed is polymerized, but by adjusting the kind and amount of the reducing agent, the halogen It is also possible to polymerize a portion of the polymerizable compound where a latent image of silver halide is not formed (see Japanese Patent Application No. 60-210657).

The PS plate of the present invention is extremely advantageous for producing a lithographic printing plate, and various methods including the above-mentioned exposure / development treatment (heat development treatment, primary heating) are available for obtaining the lithographic printing plate. It is possible.

For example, the following methods can be mentioned.

That is, (1) pattern exposure → heat development → secondary heating →
Wash-off → gumming, (2) pattern exposure → heat development → secondary heating → whole surface exposure → washoff → gumming, (3) pattern exposure → heat development → pressurization → whole surface exposure →
Wash-off → gumming, (4) thermal printing → wash-off → gumming, (5) thermal printing → whole surface exposure → washoff → gumming, (6) pressure printing → whole surface exposure → washoff → gumming, etc. The method for producing a lithographic printing plate will be described in more detail by taking the method shown in (2) among the above methods as an example. Note that other methods can be similarly implemented.

First, when the PS plate of the present invention is subjected to pattern exposure and heating (primary heating) development using the above-mentioned exposing means, the microcapsules (including the core substance) in the exposed portion (the portion which becomes the non-image area) are as described above. As described above, the polymerization reaction progresses to polymerize and cure, and the heat softening temperature of the capsule rises. That is, the heat-softening temperature of the microcapsules in the cured portion is equal to or higher than the heat-softening temperature of the microcapsules in the unpolymerized (uncured) portion. Therefore, the polymerized and cured microcapsules are heated at a higher temperature (secondary heating: below the heat softening temperature of the cured portion,
Microcapsules encased in a hydrophilic binder do not soften, fuse, melt or break the microcapsules or release the core substance in the microcapsules even at a temperature higher than the thermal softening temperature of the uncured portion. Exists in the state of. On the other hand, the microcapsules in the unexposed area exist in an uncured state, and the microcapsules in this area (the area to be the image area) are stable under normal handling and under normal conditions, but By heating at high temperature (secondary heating: below the heat-softening temperature of the microcapsules in the hardened portion, above the heat-softening temperature of the microcapsules in the uncured portion), softening, fusion bonding, melting, destruction, Alternatively, the core substances in the microcapsules are mixed with each other to form a lipophilic uniform film to form an image area (ink-accepting area). Next, the above-mentioned hardened microcapsule portion can be easily removed from the support by washing off, and a non-image area (hydrophilic portion) can be obtained. Further, the uniform lipophilic film (image area) obtained as described above can be made more durable (strong) by exposing the entire surface. In addition, gumming of arabic rubber or the like is usually performed in order to prevent the hydrophilicity of the support which becomes the non-image area from being lowered as described above.

As described above, a lithographic printing plate having an image area (lipophilic) and a non-image area (hydrophilic) can be produced.

In the above manufacturing method, the secondary heating can be included in the first heat development. That is, heating may be continuously performed at a certain suitable temperature (a constant temperature may be changed stepwise or with a temperature gradient). Also,
It is also possible to pressurize using a pressurizing means instead of the secondary heating and break the microcapsules to form a lipophilic uniform film as described above. In this case, the pressurization may be performed simultaneously with the secondary heating or at the same time. Further, since it is possible to perform printing immediately by directly removing the microcapsules in the non-image area on the printing machine without performing wash-off and gumming, it is a very simple and particularly preferable method.

In the above description, a method for producing a lithographic printing plate obtained by using a system for polymerizing a polymerizable compound in a portion where a latent image of silver halide is formed is generally performed. As described above, a lithographic printing plate can be similarly obtained in a system in which a polymerizable compound in a portion where a latent image is not formed is polymerized.

The PS plate of the present invention is advantageously used for offset printing and the like.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

[Example 1] [Preparation of PS plate] A PS plate was prepared as follows.

Preparation of Silver Halide Emulsion 40 g of gelatin and potassium bromide were dissolved in 3 l of water, heated to 50 ° C., and 34 g of silver nitrate dissolved in 200 ml of water was added over 10 minutes while stirring. Then potassium iodide 3.
What dissolved 3 g in 100 ml of water was added over 2 minutes. The pH of the silver iodobromide emulsion thus obtained was adjusted and allowed to settle,
After removing the excess salt, the pH was adjusted to 6.0 to obtain a tetradecahedral monodisperse silver iodobromide emulsion having an average grain size of 0.2 μm. The yield of emulsion was 400 g.

Preparation of benzotriazole silver emulsion 28 g of gelatin and 13.2 g of benzotriazole were dissolved in 3000 ml of water. Stir this solution while maintaining it at 40 ℃
A solution of 17 g in 100 ml of water was added over 2 minutes. Excess salt was precipitated and removed by adjusting the pH of the obtained emulsion. After that, the pH was adjusted to 6.30 to obtain a benzotriazole silver emulsion. The yield of emulsion was 400 g.

Preparation of Photosensitive Composition 0.40 g of the following copolymer was dissolved in 100 g of trimethylolpropane triacrylate. To 10.8 g of the above solution, 0.22 g of Emarex NP-8 (manufactured by Nippon Emulsion Co., Ltd.), 0.65 g of the following hydrazine derivative, and 0.73 g of the following developing agent dissolved in 2.4 g of methylene chloride were added. To the above solution, a mixture of 2.4 g of silver halide emulsion, 2 g of silver benzotriazole emulsion, and 0.066 g of benzotriazole prepared as described above was added, and the mixture was stirred with a homogenizer at 15,000 rpm for 5 minutes to obtain photosensitivity. A composition was obtained.

Preparation of Photosensitive Microcapsule Liquid Addition product of xylylene diisocyanate and trimethylolpropane in the above photosensitive composition (Takenate D110N,
Polyvinyl alcohol (PVA-205, Kuraray Co., Ltd.) was prepared by dissolving 4 g of trade name, Takeda Pharmaceutical Co., Ltd.
(Manufactured by K.K.), and stirred with a homogenizer at 18000 rpm for 5 minutes to emulsify. This emulsion
The mixture was reacted for 2 hours under stirring at 1000 rpm to obtain a dispersion liquid of photosensitive microcapsules in which the photosensitive composition was contained in the microcapsules composed of the outer shell of polyurea resin.

Preparation of PS plate To 10.0 g of the microcapsule dispersion described above, a 10% aqueous solution of guanidine trichloroacetate (water: ethanol = 1: 1) was added.
1.8 g (volume ratio), 10 g of water and 0.1 g of white dextrin (manufactured by Nitto Chemical Co., Ltd.) were added to prepare a coating solution for forming a photosensitive layer. This coating solution was coated on the following aluminum support so that the weight after drying was 3 g / m ² to obtain a PS plate.

Preparation of support A substrate was prepared by the method disclosed in JP-A-56-28893. That is, an aluminum plate having a thickness of 0.24 mm was grained on its surface using a nylon brush and an aqueous suspension of 400 mesh pumice, and then washed thoroughly with water.
Then, the plate was immersed in 10% sodium hydroxide at 50 ° C. for 60 seconds for etching, washed with running water, neutralized with a 20% aqueous nitric acid solution, and washed with water. Under the condition that the voltage at the anode is 12.7 V and the ratio of the amount of electricity at the cathode to the amount of electricity at the anode is 0.8, an alternating current of sinusoidal waveform is used to generate electricity at 160 coulomb / dm ² in 1% nitric acid aqueous solution. The amount of electrolytic roughening treatment was performed. The surface roughness at this time was measured and found to be 0.6 μ (Ra display). Subsequent immersion in 30% sulfuric acid at 55 ° C
After desmutting for 2 minutes in 20% sulfuric acid, current density 2A / d
Anodization was performed so that the thickness was 2.7 g / dm ² at m ² . Then, it was immersed in a 2.5% aqueous solution of sodium silicate at 70 ° C. for 1 minute and dried.

[Evaluation as PS Plate] Two types of planographic printing plates were prepared from the PS plate obtained above and evaluated as follows.

(1) The PS plate obtained above was imagewise exposed at 200 lux for 1 second using a tungsten bulb and then placed on a hot plate heated to 125 ° C. and heated for 60 seconds. Then 1 at 170 ℃
After heating for a minute, a lithographic printing plate (A) was obtained.

(2) The PS plate obtained above was imagewise exposed to 200 lux for 1 second using a tungsten bulb and then placed on a hot plate heated to 125 ° C. and heated for 60 seconds. Then 1 at 170 ℃
After heating for a minute, the exposed portion (cured portion) which becomes the non-image area was further washed off, and then gum arabic solution was applied to obtain a lithographic printing plate (B).

Next, the lithographic printing plates (A) and (B) obtained above were mounted on a Heidelberg GTO type printing machine and printed to obtain a stain-free printed matter.

Claims (5)

[Claims] 1. A lithographic printing plate comprising a hydrophilic support and a photosensitive layer containing a hydrophilic binder and microcapsules containing a silver halide, a reducing agent and a polymerizable compound. Original version. 2. The lithographic printing plate precursor as claimed in claim 1, wherein the photosensitive layer further contains an organic silver salt, and the organic silver salt is present in the microcapsules. 3. The photosensitive layer further contains a thermal polymerization initiator,
The lithographic printing original plate according to claim 1, wherein the thermal polymerization initiator is present in the microcapsules. 4. The lithographic printing plate precursor as claimed in claim 1, wherein at least a part of the silver halide is contained in the wall material of the microcapsules. 5. The lithographic printing original plate according to claim 1, which is for heat development.